Hi,
On Fri, 07 Jan 2000 13:26:21 +0100, Benno Senoner <[EMAIL PROTECTED]>
said:
> what happens when I run RAID5+ jornaled FS and the box is just writing
> data to the disk and then a power outage occurs ?
> Will this lead to a corrupted filesystem or will only the data which
> was just written, be lost ?
It's more complex than that. Right now, without any other changes, the
main danger is that the raid code can sometimes lead to the filesystem's
updates being sent to disk in the wrong order, so that on reboot, the
journaling corrupts things unpredictably and silently.
There is a second effect, which is that if the journaling code tries to
prevent a buffer being written early by keeping its dirty bit clear,
then raid can miscalculate parity by assuming that the buffer matches
what is on disk, and that can actually cause damage to other data than
the data being written if a disk dies and we have to start using parity
for that stripe.
Both are fixable, but for now, be careful...
--Stephen
